Referee's report by William Lawrence Bragg, on a paper 'Two types of diamond' by Robert Robertson, John Jacob Fox and A E Martin Sectional committee: Physics Recommended for publication in Philosophical Transactions.The first section is interesting, though long. He does not feel competent to comment on the theoretical part of the paper and other referees should be used to determine whether this section is suitable. [Published in Philosophical Transactions A, 1934]. Endorsed on verso as received 21 September 1933. September 1933